#11073 involves a user having old FS objects around after running "fs new" and things going horribly wrong. We need to provide some kind of fencing so that if a user runs "fs new" the old objects are either forcibly removed or no longer used.

I'm partial to tagging all MDS objects with some kind of per-FS identifier (either a UUID, or the mdsmap epoch when the FS was created) that will allow the MDS and monitor to spit out a bunch of warnings. John has also suggested using RADOS namespaces to put the metadata in a different namespace each time. Identify a good plan and implement it.

History

What about checking pool stats in "fs new" and refusing to operate if either the metadata or data pools already contains >0 objects? If someone genuinely wants to point their new MDSMap at pools with existing objects, they now have "fs reset" for that.

What about checking pool stats in "fs new" and refusing to operate if either the metadata or data pools already contains >0 objects? If someone genuinely wants to point their new MDSMap at pools with existing objects, they now have "fs reset" for that.